Results 1 to 10 of about 50,208 (269)
X-ray Eclipses of Active Galactic Nuclei [PDF]
The Astrophysical Journal, 2017 X-ray variation is a ubiquitous feature of active galactic nuclei (AGNs), however, its origin is not well understood. In this paper, we show that the X-ray flux variations in some AGNs, and correspondingly the power spectral densities (PSDs) of the ...
Lu, Youjun, Yu, Qingjuan, Zhang, Fupeng
core +2 more sources
Variability and the X-ray/UV ratio of Active Galactic Nuclei [PDF]
Astronomy and Astrophysics, 2010 The observed relation between the X-ray radiation from AGNs, originating in the corona, and the optical/UV radiation from the disk is usually described by the anticorrelation between the UV to X-ray slope alpha_ox and the UV luminosity.
Antonucci, M. +3 more
core +5 more sources
Review on Active Galactic Nuclei at hard X-ray energies [PDF]
Proceedings of An INTEGRAL view of the high-energy sky (the first 10 years) - 9th INTEGRAL Workshop and celebration of the 10th anniversary of the launch — PoS(INTEGRAL 2012), 2013 Hard X-ray surveys are an important tool for the study of active galactic nuclei (AGN): they provide almost an unbiased view of absorption in the extragalactic population, allow the study of spectral features such as reflection and high energy cut-off ...
Bassani, Loredana +8 more
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The Infrared-X-ray continuum correlation in Active Galactic Nuclei [PDF]
Monthly Notices of the Royal Astronomical Society, 2003 The correlation between the soft X-ray and near infrared emission from AGN is analysed using composite models by the code SUMA. We find new evidences for differences in ranges of parameters which characterize the NLR of Seyfert galaxies and LINERs ...
Campos, P. E. +2 more
core +3 more sources
X-Ray Evolution of Active Galactic Nuclei and Hierarchical Galaxy Formation [PDF]
, 2004 We have incorporated the description of the X-ray properties of Active Galactic Nuclei (AGNs) into a semi-analytic model of galaxy formation, adopting physically motivated scaling laws for accretion triggered by galaxy encounters.
A. Cavaliere +4 more
core +5 more sources
A High Fraction of Heavily X-Ray-obscured Active Galactic Nuclei [PDF]
The Astrophysical Journal, 2023 We present new estimates on the fraction of heavily X-ray-obscured, Compton-thick (CT) active galactic nuclei (AGNs) out to a redshift of z ≤ 0.8. From a sample of 540 AGNs selected by mid-infrared (MIR) properties in observed X-ray survey fields, we ...
Christopher M. Carroll +7 more
doaj +2 more sources
Rapid X-Ray Variability in Active Galactic Nuclei [PDF]
Symposium - International Astronomical Union, 1986 SummaryRecent EXOSAT observations of active galactic nuclei are presented. Unlike earlier X-ray satellites (all of which flew in low earth orbit), the deep orbit of EXOSAT allows long continuous observations of celestial X-ray sources, uninterrupted by earth occultation etc.
P. Barr +4 more
openaire +1 more source
Clustering of X-ray selected active galactic nuclei [PDF]
Monthly Notices of the Royal Astronomical Society, 1998 A total of 235 Active Galactic Nuclei (AGN) from two different soft X-ray surveys (the ROSAT Deep Survey -DRS- and the ROSAT International X-ray Optical Survey -RIXOS-) with redshifts between 0 and 3.5 are used to study the clustering of X-ray selected AGN and its evolution.
Carrera, Francisco J. +7 more
openaire +3 more sources
The Astrophysical Journal, 2023 We report on the 2019 XMM-Newton+NuSTAR monitoring campaign of the Seyfert galaxy NGC 2992, observed at one of its highest flux levels in the X-rays.
Alfredo Luminari +10 more
doaj +1 more source
X-ray absorption and reflection in active galactic nuclei [PDF]
The Astronomy and Astrophysics Review, 2009 Accepted for publication in the Astronomy and Astrophysics Review. 58 pages, 9 figures.
Turner, T, Miller, L
openaire +3 more sources